Among conventional technologies that represent the appearance (texture) such as “wrinkles” or “unevenness” of a drawing medium such as paper on a display is Patent Literature 1. Patent Literature 1 generates a combined image by alpha-blending a target image and a filter image. At this time, a loss occurs in the dynamic range of the original image. For this reason, Patent Literature 1 reproduces the dynamic range by converting gradations in an LUT converter to compensate for the loss.